Liquid crystal optical element

Abstract

According to one embodiment, a liquid crystal optical element according to one embodiment includes a substrate, a plurality of structures aligned at a prescribed pitch in each of a plurality of first areas, and a liquid crystal layer arranged across the plurality of first areas and a second area surrounding each of the plurality of first areas. The liquid crystal layer includes first liquid crystal molecules arranged in the first areas between the adjacent structures and aligned along the structures, and second liquid crystal molecules having the long axes aligned in the same direction in the second area.

What is claimed is: 
     
         1 . A liquid crystal optical element comprising:
 a substrate having a first main surface;   a plurality of structures arranged at a predetermined pitch in each of a plurality of first areas provided in a first direction and a second direction intersecting the first direction on the first main surface; and   a liquid crystal layer provided over the plurality of first areas and a second area surrounding each of the plurality of first area, wherein   the liquid crystal layer contains first liquid crystal molecules provided between the adjacent structures and arranged along the structures, in the first areas, and second liquid crystal molecules with their long axes arranged in a uniform direction, in the second area, and is cured in a state in which alignment directions of the first liquid crystal molecules and the second liquid crystal molecules remain fixed irrespective of the electric field, and   the first liquid crystal molecules and the second liquid crystal molecules are arranged such that, in a third direction orthogonal to the first and the second directions, they do not overlap an electrode for alignment control.   
     
     
         2 . The liquid crystal optical element of  claim 1 , wherein
 a width of the second area is larger than the predetermined pitch.   
     
     
         3 . The liquid crystal optical element of  claim 1 , further comprising:
 a partition provided on the first main surface in the second area, surrounding the first area, and formed of the same material as the structures, wherein   a width of the partition is larger than a width of the structures.   
     
     
         4 . The liquid crystal optical element of  claim 1 , further comprising:
 a thin film provided between the structures in the first area and covering the first main surface, wherein   the thin film is formed of the same material as the structures.   
     
     
         5 . The liquid crystal optical element of  claim 1 , further comprising:
 an alignment film provided between the liquid crystal layer and the substrate in the second area and being in contact with the liquid crystal layer.   
     
     
         6 . The liquid crystal optical element of  claim 5 , further comprising:
 an alignment film provided between the liquid crystal layer and the substrate in the first area and being in contact with the liquid crystal layer.   
     
     
         7 . The liquid crystal optical element of  claim 1 , wherein
 the plurality of structures include a plurality of first structures in an arch shape, wherein   the plurality of first structures are arranged at a first pitch along the first direction and are arranged at a second pitch larger than the first pitch along the second direction.   
     
     
         8 . The liquid crystal optical element of  claim 7 , wherein
 the plurality of structures further include at least one second structure provided between the first structures adjacent in the second direction, and   the second structure extends linearly along the first direction.   
     
     
         9 . The liquid crystal optical element of  claim 7 , wherein
 long axes of the first liquid crystal molecules located between the adjacent first structures are aligned along tangents of the first structures, and   long axes of the second liquid crystal molecules are aligned in a direction substantially parallel to or substantially vertical to the first main surface of the substrate.   
     
     
         10 . The liquid crystal optical element of  claim 1 , wherein
 the liquid crystal layer contains nematic liquid crystal with alignment directions aligned in the first area.   
     
     
         11 . The liquid crystal optical element of  claim 1 , wherein
 the liquid crystal layer contains cholesteric liquid crystal in the first area.   
     
     
         12 . The liquid crystal optical element of  claim 1 , wherein the liquid crystal layer has a first main surface facing the substrate and a second main surface opposite thereto, and the second main surface is in contact with air. 
     
     
         13 . The liquid crystal optical element of  claim 1 , wherein the liquid crystal optical element does not comprise an electrode for alignment control.